Choosing a free license maybe a moral choice, but programs are released under free licenses for many reasons.

People join communities for different reasons, possibly different from the author’s one. In Bob Young wording: “a community is just a group of people that share a common interest – they don’t have to like each other”. And beyond license’s choice the community governance model is of great importance too.

All in all the license is just an element of the constitution, and as you pointed out tools – along with rights – can make the difference.

@roberto: I agree that the governance model is one of the tools to create a community. But, whatever is the reason to release software under a free license, moral choice should be one 🙂 It’s like deciding not to pollute the waters when starting any business.